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A proposal for B-physics on current latticeshttp://hdl.handle.net/2307/226
<Title>A proposal for B-physics on current lattices</Title>
<Authors>Blossier, Benoit; Dimopoulos, Petros; Frezzotti, Roberto; Herdoiza, Gregorio; Jansen, Karl; Lubicz, Vittorio; Martinelli, Guido; Michael, Chris; Rossi, Giancarlo; Shindler, Andrea; Simula, Silvano; Tarantino, Cecilia; Urbach, Carsten</Authors>
<Issue Date>2010-04-12</Issue Date>
<Is part of>JHEP</Is part of>
<Volume>2010</Volume>
<Pages>1-25</Pages>
<Abstract>A method to extract B-physics parameters (b-quark mass and fB, fBs decay
constants) from currently available lattice data is presented and tested. The approach is based on the idea of constructing appropriate ratios of heavy-light meson masses and decay
constants, respectively, possessing a precisely known static limit, and evaluating them at
various pairs of heavy quark masses around the charm. Via a smooth interpolation in
the heavy quark mass from the easily accessible charm region to the asymptotic point, B-physics
parameters are computed with a few percent (statistical + systematic) error using
recently produced Nf = 2 maximally twisted Wilson fermions data.</Abstract>Sun, 11 Apr 2010 22:00:00 GMThttp://hdl.handle.net/2307/2262010-04-11T22:00:00ZAn improved Standard Model prediction of BR(B →τν) and its implicationsfor New Physicshttp://hdl.handle.net/2307/227
<Title>An improved Standard Model prediction of BR(B →τν) and its implicationsfor New Physics</Title>
<Authors>Bona, Marcella; Ciuchini, Marco; Franco, Enrico; Lubicz, Vittorio; Martinelli, Guido; Parodi, Fabrizio; Pierini, Maurizio; Schiavi, Carlo; Silvestrini, Luca; Sordini, Viola; Stocchi, Achille; Tarantino, Cecilia; Vagnoni, Vincenzo</Authors>
<Issue Date>2010-02-25</Issue Date>
<Is part of>Physics Letters B</Is part of>
<Volume>687</Volume>
<Pages>61-69</Pages>
<Abstract>The recently measured B →τν branching ratio allows to test the Standard Model by probing virtual
effects of new heavy particles, such as a charged Higgs boson. The accuracy of the test is currently
limited by the experimental error on BR(B → τν) and by the uncertainty on the parameters f B and
|Vub|. The redundancy of the Unitarity Triangle fit allows to reduce the error on these parameters and
thus to perform a more precise test of the Standard Model. Using the current experimental inputs, we
obtain BR(B →τν)SM = (0.84±0.11)×10−4, to be compared with BR(B →τν)exp = (1.73±0.34)×10−4.
The Standard Model prediction can be modified by New Physics effects in the decay amplitude as well
as in the Unitarity Triangle fit. We discuss how to disentangle the two possible contributions in the case
of minimal flavour violation at large tan β and generic loop-mediated New Physics. We also consider two
specific models with minimal flavour violation: the Type-II Two Higgs Doublet Model and the Minimal
Supersymmetric Standard Model.</Abstract>Wed, 24 Feb 2010 23:00:00 GMThttp://hdl.handle.net/2307/2272010-02-24T23:00:00ZfB and fBs with maximally twisted Wilson fermionshttp://hdl.handle.net/2307/228
<Title>fB and fBs with maximally twisted Wilson fermions</Title>
<Authors>Blossier, Benoit; Dimopoulos, Petros; Frezzotti, Roberto; Herdoiza, Gregorio; Jansen, Karl; Lubicz, Vittorio; Martinelli, Guido; Michael, Chris; Rossi, Giancarlo; Sanfilippo, Francesco; Shindler, Andrea; Simula, Silvano; Tarantino, Cecilia; Urbach, Carsten; Wagner, Marc</Authors>
<Issue Date>2010</Issue Date>
<Pages>151-158</Pages>
<Abstract>We present a lattice QCD calculation of the heavy-light decay constants fB and fBs performed
with Nf = 2 maximally twisted Wilson fermions, at four values of the lattice spacing. The decay
constants have been also computed in the static limit and the results are used to interpolate the
observables between the charmand the infinite-mass sectors, thus obtaining the value of the decay
constants at the physical b quark mass. Our preliminary results are fB = 191(14)MeV, fBs =
243(14)MeV, fBs/ fB = 1.27(5). They are in good agreement with those obtained with a novel
approach, recently proposed by our Collaboration (ETMC), based on the use of suitable ratios
having an exactly known static limit.</Abstract>Thu, 31 Dec 2009 23:00:00 GMThttp://hdl.handle.net/2307/2282009-12-31T23:00:00ZStatus of the Unitarity Triangle Analysishttp://hdl.handle.net/2307/239
<Title>Status of the Unitarity Triangle Analysis</Title>
<Authors>Bona, Marcella; Ciuchini, Marco; Franco, Enrico; Lubicz, Vittorio; Martinelli, Guido; Parodi, Fabrizio; Pierini, Maurizio; Schiavi, Carlo; Silvestrini, Luca; Sordini, Viola; Stocchi, Achille; Tarantino, Cecilia; Vagnoni, Vincenzo</Authors>
<Issue Date>2009</Issue Date>
<Pages>160-163</Pages>
<Abstract>We present an update of the Unitarity Triangle (UT) analysis, within the Standard Model (SM)
and beyond. Within the SM the main novelties are the inclusion in eK of the contributions of
x and fe 6= p /4 pointed out by A. J. Buras and D. Guadagnoli, and an accurate prediction of
BR(B→tn), by using the indirect determination of |Vub| from the UT fit, which can be compared
to the present experimental result. In the generalization of the UT analysis to investigate New
Physics (NP) effects, the estimate of x is more delicate and only the effect of fe 6= p /4 has
been included. We confirm an hint of NP in the Bs-¯Bs mixing at the 2.9s level, which makes a
comparison with new experimental data certainly desired.</Abstract>Wed, 31 Dec 2008 23:00:00 GMThttp://hdl.handle.net/2307/2392008-12-31T23:00:00ZFirst evidence of new physics in b ↔ s transitionshttp://hdl.handle.net/2307/229
<Title>First evidence of new physics in b ↔ s transitions</Title>
<Authors>Bona, Marcella; Ciuchini, Marco; Franco, Enrico; Lubicz, Vittorio; Martinelli, Guido; Parodi, Fabrizio; Pierini, Maurizio; Schiavi, Carlo; Silvestrini, Luca; Sordini, Viola; Stocchi, Achille; Vagnoni, Vincenzo</Authors>
<Issue Date>2009-12</Issue Date>
<Is part of>PMC Physics A</Is part of>
<Volume>3</Volume>
<Abstract>We combine all the available experimental information on Bs mixing, including the very
recent tagged analyses of Bs → J/Ψϕ by the CDF and DØ collaborations. We find that the
phase of the Bs mixing amplitude deviates more than 3σ from the Standard Model
prediction. While no single measurement has a 3σ significance yet, all the constraints show
a remarkable agreement with the combined result. This is a first evidence of physics
beyond the Standard Model. This result disfavours New Physics models with Minimal
Flavour Violation with the same significance.</Abstract>Mon, 30 Nov 2009 23:00:00 GMThttp://hdl.handle.net/2307/2292009-11-30T23:00:00Zf_B and f_Bs with maximally twisted Wilson fermionshttp://hdl.handle.net/2307/403
<Title>f_B and f_Bs with maximally twisted Wilson fermions</Title>
<Authors>ETM Collaboration; Blossier, Benoit; Dimopoulos, Petros; Frezzotti, Roberto; Herdoiza, Gregorio; Jansen, Karl; Lubicz, Vittorio; Martinelli, Guido; Michael, Chris; Rossi, Giancarlo; Sanfilippo, Francesco; Shindler, Andrea; Simula, Silvano; Tarantino, Cecilia; Urbach, Carsten; Wagner, Marc</Authors>
<Issue Date>2009</Issue Date>
<Pages>151</Pages>
<Abstract>We present a lattice QCD calculation of the heavy-light decay constants f_B and f_Bs performed with Nf=2 maximally twisted Wilson fermions, at four values of the lattice spacing. The decay constants have been also computed in the static limit and the results are used to interpolate the observables between the charm and the infinite-mass sectors, thus obtaining the value of the decay constants at the physical b quark mass. Our preliminary results are f_B=191(14) MeV, f_Bs=243(14) MeV, f_Bs/f_B=1.27(5). They are in good agreement with those obtained with a novel approach, recently proposed by our Collaboration (ETMC), based on the use of suitable ratios having an exactly known static limit.</Abstract>Wed, 31 Dec 2008 23:00:00 GMThttp://hdl.handle.net/2307/4032008-12-31T23:00:00Z